Burner ignition means and piezoelectric crystal actuator means therefor or the like



3,490,857 ACTUATOR Jan. 20, 1970 A. L. GOOD BURNER IGNITION MEANS AND PIEZOELECTRIC CRYSTAL MEANS THEREFOR OR THE LIKE 2 Sheets-Sheet 1 Filed March 15, 1968 I3 l2 5 14 IT 6 4 2 6 B I I I ll 5 m h. H 9 J O A II. fa IJIH w m 8 O 2 B2 7 6 II Illlill I n 5 46 2 2 0 %3 2% 1. O H. r w PO l 9 a 4 O 5 8 647 3 334 Mm INVENTOR ARTHUR L GOOD M F M HIS ATTORNEYS Jan; 20, 1970 A. L.-GOOD 3,490,857

BURNER IGNITION MEANS AND PIEZOELECTRIC CRYSTAL ACTUATOR MEANS THEREFOR OR THE LIKE Filed March 15, 1968 2 Sheets-Sheet 2 HIS ATTORNEYS United States Patent 3,490,857 BURNER IGNITION MEANS AND PIEZOELECTRIC CRYSTAL ACTUATOR MEANS THEREFOR OR THE LIKE Arthur L. Good, Elkhart, Ind., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Mar. 15, 1968, Ser. No. 713,334 Int. Cl. F23q 3/00 US. Cl. 431264 20 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a piezoelectric crystalactuator means for creating electrical sparks at a spark gap to ignite fuel issuing from a burner means disposed adjacent the spark gap, the actuator means having a crystal stack that has the stresses therein altered to create a potential differential at the electrode means by a roller means being rolled between one end means of the crystal stack and another roller means having its axis fixed in offset relation to the crystal stack so that a wedging action takes place between the moving roller means and the fixed roller means to compress and relieve longitudinal forces in the crystal stack depending upon the direction of rolling movement of the movable roller means.

This invention relates to ignition means for a fuel issuing burner means as well as to an improved piezoelectric crystal means for such ignition means or the like.

It is well known that piezoelectric crystal means can have the stresses altered therein by a squeezing action or the like to create a potential differential at a pair of electrodes means operatively interconnected to the crystal means so that when the potential differential exceeds a certain amount electrical sparking will be created across the spark gap defined between the electrode means whereby such electrical sparking can be utilized to ignite fuel issuing from a burner means.

Accordingly, no external electrical power source need be utilized for such an ignition system whereby such an ignition system is particularly adaptable for a fuel burning apparatus, such as a cooking apparatus or the like, to either ignite the pilot burner means thereof or directly ignite the main burner means thereof as is apparent in the art.

Thus, one feature of this invention is to provide an improved ignition means of the above type wherein the squeezing and relieving action being imposed upon the crystal means can be effected in a simple and economical manner.

For example, the embodiment of this invention provides a crystal stack supported for rocking movement in a frame means wherein a movable roller means is carried by a pivotally mounted lever and rolls against another roller means having its axis of rotation fixed relative to the frame means in such a manner that its axis of rotation is offset relative to the longitudinal axis of the crystal stack. In this manner, the movable roller means can be rolled between the fixed roller means and one end means of the crystal stack to effect a wedging action therebetween so as to alter the stresses in the crystal means for the aforementioned ignition purpose or the like.

Accordingly, it is an object of this invention to provide an improved ignition means for a burner means or the like, the ignition means of this invention having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved piezoelectric crystal actuator means for such an ignition means or the like, the actuator means of this invention having one or more of the novel features set forth above as hereinafter shown or described.

Other objects, uses and advantages of this invention are apparent from a reading of this description, which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGURE 1 is a schematic view illustrating the improved ignition means of this invention.

FIGURE 2 is an exploded perspective view of certain of the parts of the piezoelectric crystal actuator means of the system of FIGURE 1.

FIGURE 3 is a side view, partially in cross-section, illustrating the piezoelectric crystal actuator means of FIGURE 1 in one of its operating positions.

FIGURE 4 is a view similar to FIGURE 3 and illustrates the actuator means in another of its operating positions.

While the various features of this invention are hereinafter described and illustrated as being particularly adaptable to provide ignition means for a fuel burning apparatus or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide electrical sparking for other devices as desired.

Therefore, this invention is not to be limited to only the embodiment illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 1, the ignition system of this invention is generally indicated by the reference numeral 10 and comprises a piezoelectric crystal actuator means of this invention that is generally indicated by the reference numeral 11 and is utilized for creating electrical sparking at a spark gap 12 defined between a pair of spaced electrode means 13 and 14 operatively interconnected to the actuator means 11 in a manner hereinafter described. The spark gap 12 is disposed adjacent to an outlet means 15 of a pilot burner means 16 so that when fuel issues from the pilot burner means 16, the same can be ignited by electrical sparking at the spark gap 12 in a manner hereinafter described, the pilot burner means 16, in turn, being utilized for igniting fuel issuing from a main burner means 17 in a manner conventional in the art.

As illustrated in FIGURES 1 and 2, the piezoelectric crystal actuator means 11 of this invention comprises a frame means 18 having a cutout 19 therein for receiving a crystal stack 20, the crystal stack 20 comprising an outer hollow casing 21, FIGURE 3, having opposed open ends 22 and 23 respectively receiving pressure pad means 24 and 25 projecting outwardly therefrom and respectively engaging a pair of piezoelectric crystal elements 25' and 26 disposed in the casing 21 in axially aligned relation and having terminal means 27 disposed between adjacent ends thereof. The terminal means 27 is electrically interconnected by suitable cable means 28 to the previously described electrode 15 while its cooperating electrode 13 is interconnected to the frame 18 of the actuator means 11 by cable means 29.

The cutout or opening means 19 in the frame 18 defines a first pair of opposed stop edges 30 and 31 for cooperating with the right-hand pressure pad 25 to limit rocking movement of the crystal stack 20 in a manner hereinafter described. Similarly, the cutout or opening 19 l in the frame 18 defines another pair of opposed stop edges 32 and 33 for cooperating with the left-hand pressure pad means 24 in limiting the rocking movement of the crystal stack 20 relative to the frame 18.

The opposed ends of the cutout 19 in the frame 18 define arcuate edge means 34 and 35 respectively being received in annular grooves 36 and 37 of roller elements 38 and 39 whereby the axes of rotation of the roller means 38 and 39 are fixed relative to the frame means 18 and are respectively indicated by the arrows 40 and 41 in FIGURE 1.

An actuating lever for the actuating means 11 is generally indicated by the reference numeral 42 and comprises two arms 43 and 44 interconnected together at the Opposed ends thereof by end members 45 and 46 in the manner illustrated in FIGURE 2, the lever means 42 having two pairs of opposed ear means 47, 48 and 49, 50.

The roller means 38 has a shaft means 51 at the axis 40 thereof and is rotatably secured to and between the first pair of opposed ear means 47 and 48 of the lever means 42 so that when the roller means 38 is received in the arcuate end 34 of the cutout 19 as illustrated in FIG- URE 1, the roller means 38 pivotally mounts the lever means 42 to the frame means 18.

Another roller means 52 has a shaft means 53 rotatably secured to and extending between the other pair of opposed ear means 49 and 50 of the lever means 42 so as to be disposed in the cutout 19 between the roller means 38 and the pressure pad 24 as illustrated in FIGURE 1, the roller means 52 having an annular groove 54 formed therein and respectively receiving an outwardly directed substantially frusto-conical projection 55 extending from the center of a flat end wall 56 of the pressure pad 24.

The other pressure pad 25 has a similarly outwardly extending, substantially frusto-conical projection 57 extending into the annular groove 37 of the roller means 39 whereby the projections 55 and 57 on the pressure pad means 24 and 25 orient and maintain alignment of the crystal stack relative to the opposed roller means 52 and 39.

Thus, it can be seen that the roller means 52 is adapted to roll against the fixed roller means 38 as well as against the flat end surface 56 of the left-hand pressure pad 24 of the crystal stack 20 and since the lever means 42 is pivotally mounted to the frame 18 at the axis 40 of the fixed roller means 38, the roller means 52 has its axis of rotation 58 adapted to describe an are having its center being the axis 40 of the fixed roller means 38 when the movable roller means 52 rolls against the roller means 38.

The cutout or opening 19 in the frame 18 defines another set of opposed stop edges 59 and 60 respectively being adapted to be received in the annular groove 54 of the movable roller means 52 so as to limit rolling movement of the roller means 52 relative to the frame 18 for a purpose hereinafter described.

When the lever means 42 of the actuator 11 is disposed in the position illustrated in FIGURES l and 3, it can be seen that the longitudinal axis 61 of the crystal stack 20 passes through the axis 41 of the right-hand roller means 38 while being disposed above the axes 40 and 58 of the roller means 39 and 52, with the roller means 52 and pressure pads 24 and respectively being disposed against their cooperating stop edges 59, 32 and as illustrated in FIGURES 1 and 3.

Also, it can be seen that the axis of the fixed lefthand roller means 38 is disposed considerably below the longitudinal axis 61 of the crystal means 20 as well as well below a horizontal plane passing through the axis 58 of the roller means 52 when the lever means 42 is disposed in the position illustrated in FIGURES l and 3 for a purpose hereinafter described.

The operation of the ignition system 10 of this invention when utilizing the actuator means 11 will now be described.

Assuming that the actuator means 1 is disposed in the position illustrated in FIGURES 1 and 3, and it is desired to cause electrical sparking at the spark gap 12 to ignite fuel issuing from the outlet end 15 of the pilot burner means 16, the lever means 42, either manually or automatically, is pivoted in a clockwise direction from the position illustrated in FIGURE 3 to the position illustrated in FIGURE 4 whereby the movable roller means 52 rolls against the fixed left-hand roller means 38 as well as against the pressure pad means 24 to not only cause rocking of the crystal stack 20 from the position illustrated in FIGURE 3 to the position illustrated in FIG- URE 4, but also to provide a progressively increasing Wedging action against the crystal stack 21, because the distance between the roller means 52 and 39, as the roller means 52 is being moved from the position illustrated in FIGURE 3 to the position illustrated in FIG- URE 4, is progressively decreasing to progressively place an increasing longitudinally compressive force on the crystal elements 25 and 26 to alter the stresses therein. This altering of the stresses in the crystal elements 25 and 26 by the aforementioned squeezing action causes a potential differential at the electrodes 13 and 14 and when such potential differential exceeds a predetermined level, electrical sparking occurs at the spark gap 12 to ignite the fuel issuing from the outlet end 15 of the pilot burner means 16.

Of course, it is to be understood that as the roller means 52 is being moved from the position illustrated in FIG- URE 3 toward the position illustrated in FIGURE 4, such electrical sparking can take place at the spark gap 12 one or more times, depending upon the amount of compressive action being imposed on the crystal elements 25 and 26.

The downward rolling movement of the roller element 52 by the clockwise pivoting lever means 42 is limited by the roller means 52 and pressure pad means 24 and 25 of the crystal stack 21 respectively abutting against the lower stop edges 60, 33 and 31, as illustrated in FIG- URE 4.

Subsequently, manual or automatic return movement of the lever means 42 from the position illustrated in FIGURE 4 back to the position illustrated in FIGURE 3 progressively causes a decreasing or relieving of the compressive longitudinal force on the crystal elements 25' and 26 which also alters the stresses therein so that sparking takes place at the spark gap 12 as the lever means 42 is returning from the position illustrated in FIGURE 4 to the position illustrated in FIGURE 3.

The actuator means 11 can be so constructed and arranged that when the lever means 42 is in the position illustrated in FIGURE 4 the longitudinal axis 61 of the rocked and squeezed crystal stack 21 passes through the axes 40 and 41 of the roller means 38 and 39, with the axis 58 of the roller means 52 being above such longitudinal axis 61 of the crystal stack 21 so that the compressive force of the crystal elements 25' and 26 tending to expand will cause automatic returning of the lever means 42 from the position illustrated in FIGURE 4 back to the position illustrated in FIGURE 3 when the lever means 42 is released, because the roller means 52 has not, in eifect, gone over center so that the resulting force is to move the roller means 52 back to the position illustrated in FIGURE 3.

Should the pilot burner means 16 not be ignited upon one actuation of the lever means 42 from the position illustrated in FIGURE 3 to the position illustrated in FIGURE 4 and then back to the position illustrated in FIGURE 3, the lever means 42 can be rocked back and forth in the above manner two or more times, either automatically or manually to produce the aforementioned electric sparking at the spark gap 12 whereby the issuing fuel will be subsequently ignited.

Thus, the ignited pilot burner means 16 can, thereafter, be utilized to ignite the main burner means 17 in a conventional manner.

During the assembling operation of the actuator means 11 of this invention, in order to assure alignment and positive holding of the elements in the stacked relation illustrated in FIGURES l and 3, the frame 18 can be suitably stacked on the opposed sides thereof between the right-hand cutout portion 35 and the extreme right-hand end thereof, as generally indicated by the reference numeral 62, in order to inwardly expand the frame 18 to positively stack the elements being carried thereby in the jassembled relationship illustrated in FIGURES l and 3.

Therefore, it can be seen that this invention not only provides an improved ignition system or means for a burner means or the like, but also this invention provides an improved actuator for such an ignition means or the 'like.

. While the form of the invention now preferred has 'been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, said second roller means having an axis parallel to the axis of said first roller means, and means for moving said axis of said second roller means relative to said axis of said first roller means to alter the stresses in said crystal means.

2. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means, said moving means comprising a lever means pivotally mounted to said frame means and being interconnected to said second roller means.

3. An actuator means as set forth in claim 2 wherein said lever means is pivotally mounted to said frame means by said first roller'means.

4. An actuator means as set forth in claim 3 wherein said lever means is interconnected to said second roller means at the axis of'rotation of said second roller means.

5. An actuator means as set forth in claim 4 wherein said lever means has two pairs of opposed ear means, said first roller means having shaft means defining the axis thereof and being interconnected to and between one pair of opposed ear means to pivotally mount said lever means to said frame means, said second roller means having shaft means defining the axis thereof and being interconnected to and between the other pair of opposed ear means to interconnect said lever means to said second roller means.

6. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means, said first and second roller means having their axes disposed on the same side of the longitudinal axis of said crystal means when said actuator means is in its at rest position.

7. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means, said one end means of said crystal means comprising a pressure pad having a flat surface against which said second roller rotates.

8. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means, said frame means having opening means passing therethrough and in which said crystal means is mounted, said opening means defining a pair of opposed stop means for limiting rolling movement of said second roller means relative to said frame means.

9. An actuator means as set forth in claim 8 wherein said opening means defines a second pair of opposed stop means for limiting movement of said crystal means relative to said frame means.

10. A piezoelectric crystal actuator means comprising frame means, piezoelectric crystal means carried by said frame means and having opposed end means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means, said opposed end means of said crystal means comprising a pair of opposed pressure pads, said frame means carrying a third roller means having an axis in fixed relation to said crystal means, said pressure pads respectively being disposed in engagement with said second and third roller means.

11. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed end means, said crystal means being operatively interconnected to said electrode means, a first roller meanscarried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of-said end means of said crystal means, said second roller means having an axis parallel to the axis of said first roller means, and means for moving said axis of said second roller means relative to said axis of said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap.

12. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed ends means, said crystal means being operatively interconnected to said electrode means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap, said moving means comprising a lever means pivotally mounted to said frame means and being interconnected to said second roller means.

13. A combination as set forth in claim 12 wherein said lever means is pivotally mounted to said frame means by said first roller means.

14. A combination as set forth in claim 13 wherein said lever means is interconnected to said second roll-er means at the axis of rotation of said second roller means.

15. A combination as set forth in claim 14 wherein said lever means has two pairs of opposed ear means, said first roller means having shaft means defining the axis thereof and being interconnected to and between one pair of opposed ear means to pivotally mount said lever means to said frame means, said second roller means having shaft means defining the axis thereof and being interconnected to and between the other pair of opposed ear means to interconnect said lever means to said second roller means.

16. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed end means, said crystal means being operatively interconnected to said electrode means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap, said first and second roller means having their axes disposed on the same side of the longitudinal axis of said crystal means when said moving means is in its at rest position.

17. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed end means, said crystal means being operatively interconnected to said electrode means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap, said one end means of said crystal means comprising a pressure pad having a fiat surface against which said second roller rotates.

18. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed end means, said crystal means being operatively interconnected to said electrode means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap, said frame means having opening means passing therethrough and in which said crystal means is mounted, said opening means defining a pair of opposed stop means for limiting rolling movement of said second roller means relative to said frame means.

19. A combination as set forth in claim 18 wherein I said opening means defines a second pair of opposed stop means for limiting movement of said crystal means relative to said frame means.

20. In combination, a burner means, electrode means defining a spark gap adjacent said burner means for igniting fuel issuing from said burner means when electrical sparking is created across said spark gap, frame means, piezoelectric crystal means carried by said frame means and having opposed end means, said crystal means being operatively interconnected to said electrode means, a first roller means carried by said frame means and having an axis in fixed offset relation to said crystal means, a second roller means disposed in rolling engagement between said first roller means and one of said end means of said crystal means, and means for moving said second roller means relative to said first roller means to alter the stresses in said crystal means and thereby create a potential differential at said electrode means to produce electrical sparking at said spark gap, said opposed end means of said crystal means comprising a pair of opposed pressure pads, said frame means carrying a third roller means having an axis in fixed relation to said crystal means, said pressure pads respectively being disposed in engagement with said second and third roller means.

References Cited UNITED STATES PATENTS 3,114,059 12/1963 Aufierd et a1 BIO-8.7 3,255,803 6/1966 Hach et a1. 431263 EDWARD G. FAVORS, Primary Examiner US. Cl. X.R. 310-8.7 

